This invention relates to a grid finger attachable to a grid structure for guiding articles delivered to the grid structure into compartments of containers. This invention also relates to a grid structure for use with a case packing machine, wherein the grid structure has grid fingers movable by grid finger actuators.
Case packing machines for packing aligned rows of containers into compartmentalized cases typically employ conveyors for delivering the containers from an upstream source of containers to a grid structure. The grid structure generally includes partitions arranged to form passages which correspond to compartments in the cases which are to be packed. Grid structures are often provided with yieldable grid fingers which extend downwardly from the sides of the grid structure passages for projecting into the compartments of an empty case to guide and retard the movement of the containers as the containers pass through the grid structure into the empty case. Upon delivery from the conveyor to the grid structure, the containers are positioned in the passages of the grid structure, and the grid structure is lowered with the containers to an empty case for loading the containers into a case, or the empty case may be brought upwards to the grid structure, depending on the design of the particular case packing machine.
Generally, the containers are held in the grid structure prior to being delivered to the compartments of the case by laterally shiftable rods, such as disclosed in U.S. Pat. No. 2,656,081, granted to Davis and in U.S. Pat. No. 3,570,216, granted in Frentzel, or by pivotable doors, such as disclosed in U.S. Pat. No. 3,673,756, granted to Prete et al.
The conventional shiftable rod assemblies discussed above may provide a rigid impact surface against which containers are dropped when delivered to a grid structure. The dropping of the containers on such rigid structures increases: the likelihood of breakage or damage to the containers and also results in increased noise during operation of the case packing machine.
Further, use of the conventional shiftable rod assemblies for retaining containers within a grid structure also affects the thickness dimension of the partition walls of the grid structure. This is because as a grid structure is increased in length, the weight required to be supported by the shiftable rod assembly when the containers are resting thereon is correspondingly increased. This requires for the shiftable rod assembly to be strengthened, which results, normally, in the shiftable rod assembly being made of thicker profile. Since the conventional shiftable rod assembly shifts from a container restricting position, which is directly below the passages of the grid structure, to a container discharge position, which requires for the shiftable rod assembly to be beneath the partitions of the grid structure, the partitions of the grid structure must be at least as thick as the shiftable rods so that the containers may pass beside the shiftable rods as the containers are discharged through the passages of the grid structure. Consequently, in such situations the partition walls must be made thicker, causing the containers to be further separated from one another in the grid structure. This is undesirable in that for the tight packing of containers into a case, especially where the containers are square or rectangular shaped, the containers are required to be close together in the grid structure. Hence, the thicker partition walls make more difficult the loading into a case of such square or rectangular shaped containers. Furthermore, the requirement of making the partition walls thicker may increase the cost of the grid structure and the overall bulk thereof. Again, referring to the conventional shiftable rod assemblies discussed above, such mechanisms may require linkages and camming mechanisms which are both costly and complex in the operation thereof. This becomes even more important when it is taken into account that such assemblies are constantly subjected to the impact forces of containers being dropped thereon in the grid structure, thereby increasing the likelihood of damage thereto.
Other devices have been patented which selectively push the grid fingers below the grid structure together for preventing containers released from the passages of the grid structure from falling directly into the compartments of an empty case below. Such devices are disclosed in U.S. Pat. No. 4,215,521, granted to applicant's father Thomas S. Hartness, entitled, "Article Retarding Device For A Case Loading Machine" and in U.S. Pat. No. 4,248,029, granted to applicant and applicant's father, entitled, "Case Packer Loading Device".
Grid structures are often provided with yieldable grid fingers which extend downwardly from the sides of the grid structure compartments for projecting into the compartments of an empty case to guide and retard the movement of the containers as the containers pass through the grid structure and into the empty case. Sometimes, the grid fingers wear or may become bent or broken such that they must be replaced. Replacement of the fingers can be a time consuming, tedious endeavor if the fingers are not designed for quick installation and removal.
Several types of finger members have been patented which are designed for easier installation and removal from a grid structure. For example, U.S. Pat. No. 3,271,928, granted to Wild for a packer grid, discloses a grid finger member having a recessed portion for receiving a spring member attached to the grid structure. Installation of a finger involves inserting the finger into a bracket attached to the grid structure to a position such that the spring engages the recessed portion of the finger. Removal of the finger involves depressing the spring such that the spring becomes disengaged from the recessed portion, thereby allowing the finger to be pulled from the bracket. U.S. Patent No. 4,170,096, also granted to Wild, discloses another type of finger member having a longitudinal slot which engages cylindrical collars attached to the grid structure. The finger is retained to the grid structure through a releasable interference fit between the slot and the collars.
Other patented fingers are disclosed in patents having the following U.S. Pat. Nos. 3,031,820 granted to Schulze et al; 3,788,034 and 3,911,647 granted to Hartness et al., the present inventors; U.S. Pat. No. 4,044,530 granted to Phillips; and U.S. Pat. No. 4,075,819 and U.S. Pat. No. 4,207,721 granted to Raudat et al.
A problem exists with conventional grid fingers in that the grid finger attachment mechanism may have a pronounced profile or protuberances which project into the compartments of the grid structure in a manner which obstructs or inhibits the passage of or even damages the containers or the labels thereon as the containers pass through the grid structure. Such is especially significant where boxes are to be loaded into partitioned cases since the boxes must be maintained close together during packing into the case. Further, where loading rectangular containers or boxes into close-fitting partitions of a case, the grid fingers must be relatively thin for extending between the partition and the container or box being packed. Moreover, conventional grid finger attachments typically involve the use of a variety of parts, which increases the complexity of the assembly thereof.
Additionally, a problem may exist with certain grid fingers in that they may be inserted incorrectly into the grid structure, due to the design of the grid fingers which allows them to be readily attached to the grid structure in positions other than which are correct. This not only reduces the efficiency of the grid structure but also results in additional labor being required to correct the incorrect attachment of the grid fingers to the grid structure.
Referring to the grid structure itself, another problem occurs when the articles to be delivered to the grid structure are in contact with one another. This creates a problem of both separating and guiding the articles into separate compartments of the grid structure. Otherwise, the articles may hang-up in the grid structure, possibly causing the packing machine to jam.